It is known that significant differences between the regulated nominal current and the effective current occur in the coil in a valve actuation by means of a pulse-width-modulated current (PWM current control), at least when the ratio between PWM frequency and the time constant of the coil is unfavorable. It is further known in the art that there are dependencies on external parameters such as supply voltage and temperature.
For example, the (maximum possible) currentI100%=VREFx/(RL+RDSon-LS).  (1)flows through a permanently activated inductive load (e.g. valve coil).
This current consequently depends on                the voltage at the top side of the valve, and, thus, indirectly, on the battery voltage available in the motor vehicle at terminal KL30B,        on the coil resistor RL and (to a lower degree) on the on-resistor RDSon-LS of the semiconductor element(s) used to actuate the load(s). Both resistors are highly temperature-responsive: variations of approximately 0.4% per 1° C. for the load resistor (this is e.g. the temperature coefficient for copper, real coils have a somewhat lower dependency) und 0.5% per 1° C. for RDSon-LS (e.g. Power-MOSFETs, provided on one chip) are typical values.        